RABAT, Morocco - Top seed Elise Mertens is through to the semifinals at the Grand Prix Son Altesse Royale La Princesse Lalla Meryem in Rabat, ending the resurgent Sara Errani’s run in a tightly contested straight-sets victory.

After weathering a roller coaster opening set, Mertens kicked into high gear, dropping just four games to score a 6-3, 6-1 victory, her second win over Errani in 2018.

Read more: Mertens moves on in Rabat after Siegemund retires

“Even though the score was three and one, I think it was a very tough match,” Mertens said in her on-court interview.

“[Errani] is a great player, she got a lot of balls back, and of course she has a lot of experience. All credit to her, she’s still on the tour, she’s still fit as ever. So I’m really happy that I won today - I played a good level, and I knew what to do.

“Every point I had to work - if you’re attacking, she knows what to do. She brings everything back. I was staying in the rallies and I tried to play a little bit more aggressive, and it worked this time.”

The one-sided scoreline belies a contest that was anything but, especially in the opening set which featured seven breaks of serve between the two players. Mertens enjoyed plenty of chances to attack Errani’s vulnerable serves - the Italian managed to hold serve just once during the match - but Errani kept Mertens under plenty of pressure on the return.

After edging ahead to take the opening set, Mertens raised her level to reel off the last six games in a row in the second set to end the contest after an hour and 27 minutes. The Belgian outhit Errani with three times as many winners - 33 to 11 - and stayed in the positives with 24 unforced errors to the Italian’s 20.

Up next in the semifinals, she’ll take on the winner between Katarina Zavatska and No.8 seed Hsieh Su-Wei as she seeks a spot in the final and a chance to add a third singles title to her 2018 haul.